Objective: Antioxidation of different extracts from Isatidis indigotica were studied in vitro to supply the separating base of antioxidative components. Method: The extracts were prepared by macroporous resin and anion/cation exchange resin. Their antioxidant activities were assessed by two complementary test systems

namely 1

1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP) assay. Result: The total lignin displayed strong activity in all test systems. (DPPH IC50 160.6 mg·L-1; FRAP 0.78 mmol·g-1) Banlangen Keli (DPPH IC50 595.97 mg·L-1; FRAP 0.12 mmol·g-1) showed relatively lower activity. Total organic acids and total alkaloid have a little activity. Conclusion: Antioxidative components could be justified existing in the total lignin initially.